For aquatic enthusiasts and professionals, developing and maintaining a thriving aquarium environment can include giving attention to factors beyond the selection of an aquarium environment and a collection of aquatic plants. In order to produce the organic plant materials necessary for their survival and growth, aquatic plants, like any plants, must extract carbon dioxide from the atmosphere and undergo the process of photosynthesis. During this process, a plant removes carbon dioxide gas from the atmosphere and combines the gas with water. In the ensuing chemical reaction, the carbon dioxide and water combine with light energy to create oxygen gas, which is released from the plant, and hydrogen compounds, which the plant uses for chemical energy in a process called photophosphorylation. The amount of carbon dioxide needed during photosynthesis depends directly upon the amount of light energy available.
In aquarium environments without supplemental lighting, for example, low light conditions may exist. These low light conditions may reduce the amount of carbon dioxide needed for photosynthesis. In these cases, the amount of carbon dioxide dissolved naturally in the aquarium environment may be of insufficient concentration for existing aquatic plants to undergo photosynthesis. In order for the plants to thrive and grow, however, it may be necessary to increase available levels of both light and carbon dioxide gas. By adding only supplemental lighting to an aquarium environment, photosynthesis of the aquatic plants may be limited by inadequate amounts of carbon dioxide naturally present in the aquarium environment.
To overcome the problem of an inadequate concentration of dissolved carbon dioxide gas in an aquarium environment, it is known to inject carbon dioxide gas into the aquarium environment to increase this concentration. A number of existing methods for injecting carbon dioxide gas into a liquid exist on the market. In one method of continuously injecting carbon dioxide gas into a liquid, a regulated supply of carbon dioxide gas is employed. The regulated supply of carbon dioxide gas may be directed into an aquarium environment with a section of tubing. Apparatus to aid in the dissolution of a gas with water, such as gas reactors, mixing stones, or other similar apparatus, may be attached about the aquarium environment end of the tubing to increase the rate at which carbon dioxide gas is absorbed into the aquarium environment.
In order to provide a means for controlling the concentration of carbon dioxide gas introduced into an environment, a number of apparatus have been developed, including those which combine a gas regulator with a solenoid valve in a manner so that the solenoid opens the valve to allow the carbon dioxide gas to enter the aquarium environment until the desired concentration of the gas has been achieved in the aquarium environment, and then closes to selectively block the flow of carbon dioxide gas when the desired concentration of the gas has been achieved in the aquarium environment. When the concentration drops below a threshold concentration, the solenoid then again opens and allows the flow of gas to resume to the aquarium. Among the problems with this manner of controlling the concentration of carbon dioxide is a lack of precision. As the flow of gas is blocked and resumed, the gas concentration within the aquarium environment fluctuates.
Furthermore, certain applications in salt water aquarium environments require the injection of controlled amounts of gases. Specifically, certain levels of calcium are required in a salt water environment so that the shells of invertebrates may develop, such as the shells of mollusks or snails. One method of maintaining adequate levels of calcium in a saltwater environment is by dissolving a controlled amount of a calcium-based substrate using a calcium reactor. At normal aquarium pH levels, calcium from the substrate is insoluble. However, carbon dioxide gas can be injected into the reactor chamber containing the substrate, thereby lowering the pH of the water contained within the chamber. At this lower pH, calcium from the substrate dissolves into the water. In order to control the rate at which the calcium dissolves, and therefore the concentration of calcium in the aquarium environment, it is necessary to control the rate at which gas is injected into the calcium reactor.
Because the relationship between the concentration of carbon dioxide gas and available light energy is important for the health of aquatic life, particularly aquatic plant life, a precise means of adding carbon dioxide gas to an aquatic environment and thereby helping to control the concentration of carbon dioxide gas within an aquatic environment is needed.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.